Attention Deficit Hyperactivity Disorder (ADHD) is an impairing disorder affecting millions of children, adolescents and adults. Deficits in motivation are repeatedly implicated in the conceptualization of ADHD. Clinically, ADHD patients and/or their caregivers routinely complain about lack of motivation. However, experimentalists manipulate motivation using external incentives (e.g., money), while deficits in ADHD are most evident under conditions without external or immediate reward. Recent work by the investigative team has demonstrated pronounced individual differences in the extent to which healthy volunteers are able to self-stimulate ventral tegmental area (VTA) activation by imagining personalized scenarios to increase motivation. Previously, we have shown these same reward-related brain regions are dysregulated in ADHD. The overall goals of the first phase of this R21/R33 application are to 1) investigate the ability of adults with ADHD to sustain activation of the dopamine-containing regions of the midbrain without immediate extrinsic rewards; 2) to determine whether this ability can be enhanced with real-time fMRI feedback (RTFF); and 3) to assess the extent to which VTA self-activation is associated with clinically relevant motivation and cognitive endpoints. If we achieve the R21 goals, we will proceed to the second (R33) phase of the project, which will involve a small, randomized, proof-of-concept trial to compare the efficacy of RTFF and a no-feedback control condition on validated measures of ADHD functioning. If the aims of this project are achieved, we will have - for the first time - a reliabe non-pharmacological approach, free from potential adverse side effects of pharmacological interventions, for targeting brain activation in a system that is directly implicated in clinical impairment in individuals with ADHD. If our hypotheses are confirmed, this project will serve as a foundation for larger controlled trials to evaluate efficacy, effectiveness, and scalability.